No, they're not crazy. It just looks that way for Red Bull team members at EAA AirVenture

Kirby Chambliss flies his plane in a corkscrew fashion around Miles Daisher as he free falls in a wing suit Wednesday during the afternoon airshow at EAA AirVenture in Oshkosh. Daisher has completed around 5,000 wing suit jumps.(Photo: Amber Garrett/For USA TODAY NETWORK-Wisconsin)

It’s something that’s just there, keeping them rooted to the ground. But for the Red Bull Air Force, whose business is to tumble, plunge, fly, swoop and drop toward terra firma, gravity weighs heavily on them.

On Wednesday at EAA AirVenture, Red Bull Air Force team members performed a unique show featuring an aerobatic plane and helicopter carrying four skydivers.

The 20-minute show started with JT Holmes leaping out of a helicopter at just 1,000 feet — normally the lowest altitude for skydiving is 2,500 feet — wearing special gear that allowed him to dive very quickly before pulling his parachute’s ripcord, similar to a BASE jump.

He was followed by Jon Devore and Amy Chmelecki in fast parachutes with smaller canopies diving head first and then Miles Daisher, clad in a wingsuit he used to glide like a flying squirrel.

Yes, they all know it sounds crazy to jump out of a perfectly good helicopter.

“People use the term adrenaline junkie. I prefer adrenaline enthusiast,” Holmes saiid shortly before performing.

While most helicopters are in serious trouble if they’re upside down, an MBB Bo 105 is a special twin-engine aerobatics helicopter built to allow Red Bull pilot Aaron Fitzgerald to do just that. Fitzgerald took off with Devore, Chmelecki, Holmes and Daisher, ascending like an elevator over Wittman Regional Airport in Oshkosh and then watched his passengers tumble out.

Fitzgerald, a Washington state native, has been flying helicopters for 25 years; this is his first year performing with the Red Bull Air Force. During the afternoon air show, Fitzgerald flew between 1,000 and 6,000 feet at a top speed of 100 knots and then performed stunts like barrel rolls and hammerheads. He starts out at every air show with a helicopter full of people and returns alone.

“It’s hard to get used to. One minute I’m in a helicopter with my friends, high-fiving them and having a good time, and then they jump out and I’m by myself,” said Fitzgerald.

The team performs different maneuvers depending on the show. At Oshkosh, it features Fitzgerald in a helicopter, aerobatics pilot Kirby Chambliss in a plane, and the four skydivers.

Even though it looks reckless, it’s not, said Devore, who has performed skydiving stunts in several movies including “Iron Man 3.”

“Obviously, no, we’re not crazy. Everyone on the team has a similar story. We found a passion and we’ve trained for years. It didn’t happen overnight,” said Devore, who arrived in Oshkosh from Japan where he skydived into a stadium before a soccer game 36 hours earlier.

Each winter the Red Bull team meets at Chambliss’ home in California to plan the next season’s performances. They dream up routines to showcase the different aerial disciplines, practice and perform for their friends and family to get feedback. Sometimes, it doesn’t turn out like they expect.

“We’ll get down on the ground and say ‘Wow, that was the coolest thing in the world,’ but the people on the ground will tell us it doesn’t translate,” Devore said.

Holmes went on his first BASE jump in Idaho the day after his 22nd birthday. Then he learned skydiving, speed riding, which is like skiing but with an open parachute, paragliding and flying in a wingsuit.

While BASE jumping can be dangerous since it’s leaping off a fixed structure and quickly opening a parachute, Holmes loves it and has figured out how to earn a living by falling to Earth.

“BASE is the purest and most potent form of acceleration that a human can experience. Zero to 100 mph in about eight seconds with no engines, just gravity,” said Holmes.

Chmelecki has performed 18,000 skydive jumps since her first at the age of 18. Six years ago, she was hired for the Red Bull team. When she and Devore jumped out of the helicopter Wednesday, they looped around each other before quickly floating down to the air show grounds.

When she’s performing, Chmelecki said she’s thinking about “every moment ahead of me, the aircraft and the winds. Once my chute opens I check to make sure everything is OK and then it’s sashaying down. It’s really an ‘in the moment’ thought process.”

Daisher got to jump last in a large wingsuit. A minimum of 200 parachute jumps is required before trying a wingsuit.

Openings in the suit fill with air as the jumper falls until the suit becomes rigid and feels like flying in a fixed wing aircraft. To change direction, Daisher turns his head or dips his shoulder in micro-movements. Wing-suit fliers can dive to build speed and then point upwards to gain altitude.

“Usually the first thing that goes through my mind is — this is so amazing,” said Daisher.

As Daisher barreled forward with white smoke trailing behind him, Chambliss flew his Edge 540 plane in loops around him. Finally, Daisher pulled open a small parachute and floated down to the ground.